This invention relates to a waste water cleaning system for use with apparatus for processing exposed lithographic plates, the processing apparatus receiving wash water for removing chemicals used in the processing. A centrifuge is connected to receive waste water from the processing apparatus and removes contaminants in the waste water.
With the enactment of the Clean Water Act, disposal of waste water through sewer systems has taken on added importance and complexity. The Clean Water Act regulates the effluent coming from all sources whether they be publicly or privately owned treatment plants, industry, home, etc. Placing an effluent in a publicly or privately owned sewer passes the responsibility of adhering to the Clean Water Act on to the treating facility. In order to meet the limitations set forth by the Clean Water Act, treatment facilities, in turn, have issued their own ordinances regulating what can and can not be placed in the sewer. These ordinances generally regulate the type and amount of solid material contained in the waste water for sewer disposal.
Apparatus designed for the processing of exposed lithographic plates typically includes a source of water for rinsing or washing residues including unexposed sensitizer, polymer, photopolymer, spent developer, and spent finisher from the lithographic plate and transport rollers. These residues include solid contaminants such as resins, pigments, fillers, clays, talcs, and other water insoluble organic and inorganic compounds which may not be placed in sewers due to environmental regulations. Moreover, because these solid contaminants are heavy and/or sticky, the drain lines may become clogged and require frequent cleaning.
Filtering systems have proved unsatisfactory for removing the contaminants from the waste water. The small micron size filters required for separation will clog rapidly because of the volume of solid waste and the filters will become quickly blinded or clogged due to resinous matter contained in the waste water. Down-time during which the filters are being replaced or cleaned will result in lost production.